Spontaneous tumor lysis syndrome in a patient with newly diagnosed metastatic colonic adenocarcinoma.

Acute tumor lysis syndrome in the absence of cytotoxic therapy is an uncommon event but has been reported with hematologic malignancies. The case described below illustrates spontaneous tumor lysis syndrome in the context of a rapidly proliferating metastatic colonic adenocarcinoma. Clinicians should consider ordering phosphate, uric acid, and calcium when assessing patients with recently diagnosed or suspected malignancy.